1. Field of the Invention
This invention relates to cutting torch tips. More particularly, this invention relates to a cutting torch tip that can be employed for beveling high strength steels as well as common carbon steels when cutting at angles greater than 45.degree. with respect to the perpendicular and produce a smooth cut.
2. Description of the Prior Art
The prior art has seen the development of a wide variety of torch tips, including cutting torch tips. As is recognized, cutting oxygen passes through an orifice, usually centrally located, in the tip. Surrounding the orifice are a plurality of smaller orifices called preheat orifices that pass a mixture of fuel gas and oxygen to preheat the metal for cutting. The admixture of fuel gas and oxygen burn to insulate the cutting oxygen from contamination by surrounding air. Consequently, the preheat orifices must be located precisely around the cutting orifice in a proper orientation. Torch tips for these features have in the past been made by three basic methods producing two basic styles of tips.
The older style is a single piece torch tip. One way of making this style of tip is by drilling. First, a solid blank of material, such as copper, is shaped in the form of a torch tip. Next, the cutting orifice and the preheat orifices are formed in the blank by drilling. Since drilled holes are limited in the minimum diameter obtainable, it is often desirable to make the orifices smaller. This improves combustion properties such that the fuel gas burns more efficiently, heating the work piece better. In this method, holes have also been formed by inserting piano wires in the drill holes and swaging the tip around the wires, then pulling the wires free. The problem with this method is that it is slow, the drills do not drill straight enough to optimally locate the orifices and the drills frequently break. Moreover, the number of preheat orifices that can be located about the cutting orifice is limited because of the disadvantages of this method. Another method of making single piece type torch tip is by swaging or drawing together two separate pieces. U.S. Pat. Nos. 3,716,902, and 2,254,757 reveal such a method. This method is less expensive than the first but also has problems in that the number and shape of the preheat orifices is still limited and the precise orientation of preheat orifices is less than optimal.
The other style of torch tip is a two piece design. An example of this type of tip is revealed in U.S. Pat. No. 2,468,824. The outer piece of this tip is made by forming a shell of smooth interior. The inner piece is made by milling rectangular slots in the exterior of a blank piece of metal and drilling a cutting orifice through the center thereof. The smooth inner surface of the outer piece and the mill slots of the inner piece combine to form the preheat orifices. This method is advantageous in that an increased number of preheat orifices is possible. In the prior art of this type, however, the tips not been satisfactory when trying to form a smooth, beveled cut where the degree of bevel is more than 45.degree. with respect to the perpendicular; for example, in the range of 45.degree.-90.degree. with respect to a vertical plane when the work surface is horizontal. Apparently, there has been a concentrated flame from which the heat was reflected from the cutting surface of the work piece such that even if cutting was possible at all, it was a ragged cut that had to supplementarily processed; particularly, with high strength steels.
Typical of other prior art patents are U.S. Pat. Nos. 3,838,820; 3,558,062; 2,351,787; 1,731,265; and 1,186,962. These patents were thought to have possibilities; but when tested they all developed the same reflecting heat problem such that even where a beveled cut was possible, it was a jagged cut that required supplemental working.
From the foregoing, it can be seen that none of the prior art torch tips produced a type flame that would bevel and produce a smooth cut when the angle of bevel was between 45.degree.-90.degree. with respect to the perpendicular, or line perpendicular to the surface of the work piece at the point of beveling.